use cleanenv

---

examples/use-cleanenv/use_cleanenv.go

package main

// go get -u github.com/ilyakaznacheev/cleanenv

import (
    "fmt"
    "os"

    "github.com/ilyakaznacheev/cleanenv"
)

type configDatabase struct {
    Port string `yaml:"port" env:"PORT" env-default:"5432"`
    Host string `yaml:"host" env:"HOST" env-default:"localhost"`
    // Name     string `yaml:"name" env:"NAME" env-default:"postgres"`
    // User     string `yaml:"user" env:"USER" env-default:"user"`
    // Password string `yaml:"password" env:"PASSWORD"`
}

var cfg configDatabase

func main() {
    err := cleanenv.ReadConfig("config.yml", &cfg)
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    fmt.Printf("port: %v\n", cfg.Port)
    fmt.Printf("host: %v\n", cfg.Host)
}

examples/use-cleanenv/config.yml

port: 23